GB2199365A - Tailgate mechanism - Google Patents

Abstract

A tailgate (28) is pivotally mounted at the upper end of a container (10) by a double hinge arrangement (26) so as to hang by gravity over an outlet part of the container, the tailgate (28) being hinged (at 53) to a sub- assembly of hinge plates (40) which is itself hinged (at 35) to the container such that the suspension axis (53) for the tailgate provided by the first hinge can be raised relative to the container outlet by pivotal displacement of the sub-assembly about the second hinge axis (35). An abutment (58) engages the plates (40) is the closed position of the tailgate and a locking mechanism comprising C-shaped lugs on a rotatable shaft engages rods on the lower end of the tailgate in the closed position. <IMAGE>

Description

DESCRIPTION TAILGATE MECHANISM.

The present invention is concerned with tailgate mechanisms for tipping wagons, compacting containers, open containers and. the like, which have a pivotable.

tailgate which allows material to be removed or dumped from the wagon or container.

By way of illustration, a typical tipping wagon of the type used, for example, for carrying rubbish to a tip, is fitted conventionally with a vertically suspended tailgate which can pivot about a horizontal suspension axis disposed at or adjacent the upper rear end of an open container. When the lower end of the tailgate is released from a locking mechanism and the front end of the container is raised, rubbish in the container is displaced by gravity twoards the rear of the container where it can then pivot open the tailgate about its suspension axis to enable the rubbish to be released and deposited on the ground.

The wagon is often driven forward during this tipping operation.

With this conventional arrangement, it is found that the efficiency of release of material from the container is reduced as a result of the fact that, even when it has pivotted, the tailgate remains in a position where it tends to restrain the free ejection of material from the container.

It is an object of the present invention to provide a tailgate mechanism in which the efficiency of release of material from the container during tipping is increased.

In accordance with the present invention there is provided a tailgate mechanism in which a tailgate is pivotally mounted at the upper end of a container by a double hinge arrangement so as to hang by gravity over an outlet part of the container, the tailgate being hinged to a sub-assembly which is itself hinged to the container such that the suspension axis for the tailgate provided by the first hinge can be raised relative to the container outlet by pivotal displacement of the sub-assembly about the second hinge.

Preferably, the sub-assembly comprises a pair of hinge plates which are pivotally connected to the body of the container by said second hinge, the hinge plates extending rearwardly of the second hinge towards a rear end of the container containing said outlet and being pivotally connected to the upper end of the tailgate by said first hinge.

Advantageously, abutment means are provided for limiting the pivotal movement of the hinge plates relative to the container body in a direction corresponding to downward displacement of the tailgate.

By enabling the suspension axis of the tailgate to be selectively lifted, the taiigate is capable of being displaced to positions in which it provides significantly less hindrance than hitherto to the ejection of material and objects from the container, particularly in cases where such material and/or objects are to be ejected from the container simply by tipping the container about its discharge end.

The invention is described further hereinafter., by way of example, with reference to the accompanying drawings, in which: Fig .1 is a diagrammatic perspective view of part Of a tipping container fitted with one embodiment of a tailgate mechanism in accordance with the present invention; Fig.2 is a diagrammatic side view of the double hinge arrangement in the tailgate mechanism of Fig.l; Fig.3 is a rear view of part of the double-hinge arrangement of Fig.2; Fig.4 is a sectional view of part of one hinge of the double-hinge arrangement; Fig.5 is a sectional view of part of the second hinge of the double-hinge arrangement; Fig.6 is a rear view of part of a locking mechanism for the tailgate; and Fig .7 is a side view of the locking mechanism of Fig.6.

Referring first to Fig.l, there is shown the rear end portion of a tippable open container 10 having a rigid frame 12 which supports side walls 14,16 and a base wall 18. The rigid frame 12 includes a pair of top rails 20, a pair of vertical end struts 22 (only one visible in Fig.l) and a plurality of vertical strengthening ribs 24 (only one visible). Pivotally suspended from the upper rear end of the frame 12 by a double-hinge arrangement 26 is a tailgate 28 comprising a framework of rigid beams carrying a panel 30 which defines the rear wall of the container 10.

As explained in detail below, the double-hinge arrangement 26 provides not only for the tailgate to pivot about its principal suspension axis but also permits the latter axis to rise relative to the container frame 12. This is achieved by mounting the principal suspension axis on a pair of sub-assemblies which are themselves mounted pivotally on the main frame 12.

Referring now also to Figs. 2 to 5, there is rigidly mounted to the rear end of each of the top rails 20 of the container 10 a respective main mounting plate 32. The mounting plates 32 carry a pair of hinge pins 34 fixed to the mounting plates to define a common pivotal aixs 35 on which there is pivotally mounted, by way of respective annular bushes (optional), a pair of hinge plates 40. Lateral separation of the hinge plates 40 and mounting plates 32 is maintained by spacers 42. The hinge pins 34 thus define first hinges A by which the' hinge plates can pivot relative to the container frame 12.

The hinge plates 40 extend rearwardly relative to the hinges A and at their rearmost ends are pivotally connected, by means of hinges B, to the upper end of the tailgate 28. To this end, (where rigidity requires), there is mounted in the upper cross-beam 44 of the tailgate 28 a pair of pivot blocks 46 carrying respective outwardly directed pivot pins 48 which are pivotally received, by way of annular bushes 50 (optional), in apertures 52 in the rearmost ends of the hinge plates 40, to thereby define a second pivotal axis 53. The hinge plates 40 are retained on the pins 48 by means of retaining plates 54.

Two further plates 56 are welded to the sides of the container frame adjacent the main mounting plates 32 and carrying respective abutment, blocks 58 which serve to engage the undersides of the hinge plates 40 and prevent these -members from pivotting downwardly beyond the approximately horizontal position shown in Fig.2.

It wll be appreciated that, by virtue of the above-described construction, the tailgate can pivot about the axis 53 in a manner corresponding to the pivotal motion of a conventionally suspended tailgate. In addition, however, by pivotting about the axis 35, the hinge plates 40 can raise the position of the axis 53 and so enable the position of the tailgate as a whole to be raised. The tailgate is thereby enabled to be displaced to positions in which it provides far less hindrance to the ejection of material and objects from the container than is the case with conventionally suspended tailgates.

It should be emphasised that the invention is not limited to the precise configuration shown in the drawings. Thus, the size and shape of the main mounting plates and the hinge plates and the relative height and longitudinal spacing of the hinges A and B may be altered to suit the practical circumstances.

As indicated in Fig.l and as shown in more detail in Figs. 6 and 7, a mechanism is provided at the lower end of the tailgate for selectively locking the tailgate in its closed position. The lower cross beam 60 of the tailgate is formed of angle iron and carries a pair of rods 62 which are fixed to the beam 60 by way of support plates 64 at spaced positions 65 and 66. Pivotally mounted on the container body at 68 is a further rod 70 carrying a pair of generally C-shaped clamping lugs 72 which can be engaged over the rods.62 in one angular position of the rod 7Q to hold the tailgate firmly in the closed position. The rod 70 can be held in this position by securing an extended end of this rod 70 to a fixing bracket 74 on.the side of the container by means of a ring 76 or other fixing. When the ring is removed from the end of the rod 70, the latter rod can be pivotted to displace the clamping lugs 72 to a position in which they release the rods 62 and enable the tailgate to be displaced freely about its suspension axis 53.

Claims (9)

CLAIMS.

1. A tailgate mechanism in which a tailgate is pivotally mounted at the upper end of a container by a double hinge arrangement so as to hang by gravity over an outlet part of the container, the tailgate being hinged to a sub-assembly which is itself hinged to the container such that the suspension axis for the tailgate provided by the first hinge can be raised relative to the container outlet by pivotal displacement of the sub-assembly about the second hinge.

2. A tailgate mechanism as claimed in claim 1, wherein the sub-assembly comprises a pair of hinge plates which are pivotally connected to the body of the container by said second hinge, the hinge plates extending rearwardly of the second hinge towards a rear end of the container containing said outlet and being pivotally connected to the upper end of the tailgate by said first hinge.

3. A tailgate mechanism as claimed in claim 2, wherein abutment means are provided for limiting the pivotal movement of the hinge plates relative to the container body in a direction corresponding to downward displacement of the tailgate.

4. A tailgate mechanism as claimed in claim 3, wherein the abutment means comprise respective blocks fixed rigidly to the sides of said container and which are adapted to engage the undersides of said hinge plates for preventing the latter members from pivotting downwardly beyond an approximately horizontal position.

5. A tailgate mechanism as claimed in claim 1, 2, 3 or 4, wherein the hinge plates are pivotally mounted on hinge pins carried by respective mounting plates rigidly attached to an upper rear end of said container.

6. A tailgate mechanism as claimed in any of claims 1 to 5, including a mechanism at the lower end of the tailgate for selectively locking the tailgate in its closed position.

7. A tailgate mechanism as claimed in claim 6, wherein said locking mechanism comprises an elongate member which is rotatable about its longitudinal axis and which carries generally C-shaped clamping lugs which1 in one angular position of the elongate member, can be engaged over respective parts fixed to the lower end of the tailgate to hold the tailgate firmly in its closed position.

8. A tailgate mechanism as claimed in claim 7 wherein rotation of said elongate member is achieved by angular displacement of a rod attached to or integral with said elongate member and lying along the side of the container.

9. A tailgate mechanism substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.